lnwire: make LocalNonce an optional tlv record and fix extra data

It should be an optional record instead of an fn option. In addition,
its tlv type is bumped to be 14 as this record is also included in the
`DynCommit`. If we use tlv type 0, it will create a conflict in the msg
`DynCommit`, which is fixed in the following commit.

lnwire/dyn_ack.go

@@ -4,8 +4,6 @@ import (
 	"bytes"
 	"io"
 
-	"github.com/btcsuite/btcd/btcec/v2/schnorr/musig2"
-	"github.com/lightningnetwork/lnd/fn/v2"
 	"github.com/lightningnetwork/lnd/tlv"
 )
 
@@ -13,7 +11,7 @@ const (
 	// DALocalMusig2Pubnonce is the TLV type number that identifies the
 	// musig2 public nonce that we need to verify the commitment transaction
 	// signature.
-	DALocalMusig2Pubnonce tlv.Type = 0
+	DALocalMusig2Pubnonce tlv.Type = 14
 )
 
 // DynAck is the message used to accept the parameters of a dynamic commitment
@@ -33,7 +31,7 @@ type DynAck struct {
 	// used to verify the first commitment transaction signature. This will
 	// only be populated if the DynPropose we are responding to specifies
 	// taproot channels in the ChannelType field.
-	LocalNonce fn.Option[Musig2Nonce]
+	LocalNonce tlv.OptionalRecordT[tlv.TlvType14, Musig2Nonce]
 
 	// ExtraData is the set of data that was appended to this message to
 	// fill out the full maximum transport message size. These fields can
@@ -62,31 +60,27 @@ func (da *DynAck) Encode(w *bytes.Buffer, _ uint32) error {
 		return err
 	}
 
-	var tlvRecords []tlv.Record
-	da.LocalNonce.WhenSome(func(nonce Musig2Nonce) {
-		tlvRecords = append(
-			tlvRecords, tlv.MakeStaticRecord(
-				DALocalMusig2Pubnonce, &nonce,
-				musig2.PubNonceSize, nonceTypeEncoder,
-				nonceTypeDecoder,
-			),
-		)
-	})
-	tlv.SortRecords(tlvRecords)
-
-	tlvStream, err := tlv.NewStream(tlvRecords...)
+	// Create extra data records.
+	producers, err := da.ExtraData.RecordProducers()
 	if err != nil {
 		return err
 	}
 
-	var extraBytesWriter bytes.Buffer
-	if err := tlvStream.Encode(&extraBytesWriter); err != nil {
+	// Append the known records.
+	da.LocalNonce.WhenSome(
+		func(rec tlv.RecordT[tlv.TlvType14, Musig2Nonce]) {
+			producers = append(producers, &rec)
+		},
+	)
+
+	// Encode all records.
+	var tlvData ExtraOpaqueData
+	err = tlvData.PackRecords(producers...)
+	if err != nil {
 		return err
 	}
 
-	da.ExtraData = ExtraOpaqueData(extraBytesWriter.Bytes())
-
-	return WriteBytes(w, da.ExtraData)
+	return WriteBytes(w, tlvData)
 }
 
 // Decode deserializes the serialized DynAck stored in the passed io.Reader into
@@ -106,37 +100,22 @@ func (da *DynAck) Decode(r io.Reader, _ uint32) error {
 		return err
 	}
 
-	// Prepare receiving buffers to be filled by TLV extraction.
-	var localNonceScratch Musig2Nonce
-	localNonce := tlv.MakeStaticRecord(
-		DALocalMusig2Pubnonce, &localNonceScratch, musig2.PubNonceSize,
-		nonceTypeEncoder, nonceTypeDecoder,
+	// Parse all known records and extra data.
+	nonce := da.LocalNonce.Zero()
+	knownRecords, extraData, err := ParseAndExtractExtraData(
+		tlvRecords, &nonce,
 	)
-
-	// Create set of Records to read TLV bytestream into.
-	records := []tlv.Record{localNonce}
-	tlv.SortRecords(records)
-
-	// Read TLV stream into record set.
-	extraBytesReader := bytes.NewReader(tlvRecords)
-	tlvStream, err := tlv.NewStream(records...)
-	if err != nil {
-		return err
-	}
-	typeMap, err := tlvStream.DecodeWithParsedTypesP2P(extraBytesReader)
 	if err != nil {
 		return err
 	}
 
 	// Check the results of the TLV Stream decoding and appropriately set
 	// message fields.
-	if val, ok := typeMap[DALocalMusig2Pubnonce]; ok && val == nil {
-		da.LocalNonce = fn.Some(localNonceScratch)
+	if _, ok := knownRecords[da.LocalNonce.TlvType()]; ok {
+		da.LocalNonce = tlv.SomeRecordT(nonce)
 	}
 
-	if len(tlvRecords) != 0 {
-		da.ExtraData = tlvRecords
-	}
+	da.ExtraData = extraData
 
 	return nil
 }

lnwire/test_message.go

@@ -796,9 +796,10 @@ func (da *DynAck) RandTestMessage(t *rapid.T) Message {
 	}
 
 	includeLocalNonce := rapid.Bool().Draw(t, "includeLocalNonce")
-
 	if includeLocalNonce {
-		msg.LocalNonce = fn.Some(RandMusig2Nonce(t))
+		nonce := RandMusig2Nonce(t)
+		rec := tlv.NewRecordT[tlv.TlvType14](nonce)
+		msg.LocalNonce = tlv.SomeRecordT(rec)
 	}
 
 	// Create a tlv type lists to hold all known records which will be